This invention relates to a software controlled switch device and that permits two interconnected devices to be connected into four possible interconnected modes of operation. The switching device preferably connects with the serial output COM port and uses control line signals on the serial output COM port to selectively operate the switch means to, in turn, provide the four possible modes of interconnected operation of the devices.
In the prior art of computer controlled switching and sensing equipment, devices have been directly controlled via the PC parallel data bus or indirectly controlled via an external cable connection. Devices may also be directly controlled via a specialist interface on the bus, or indirectly via a printer or communications port.
Directly controlled devices may operate by a parallel interface, that is, by reading or writing data to certain machine addresses in the address and data busses of the computer. The presence or absence of certain data on the busses is used to control switches. Such devices do not operate with a standard memory address or standard method by which the computer may recognise the equipment. In other words, the set-up is dedicated for the particular devices and computer. This, in turn, has not facilitated the writing of software for xe2x80x9cPlug and Playxe2x80x9d compatibility.
It has been known to provide switching devices which connect a fax machine, a computer, and a modem to a telephone line but such devices themselves have not been universal and require dedicated set-up. In some cases switch means are provided within a modem, and controlled via the modem and a microprocessor of the modem. In this case it is typical to provide an AT command issued to the modem via the serial output COM port of the computer. In this case, to achieve the desired switching features it is necessary for the user to acquire a special purpose modem to connect to the fax machine and the computer. In other words, dedicated devices must be provided at the outset and there is no universal switching device which will permit interconnection of single purposes devices such as dedicated fax and a dedicated standard modem without the use of dedicated hardware and control circuits and the like in the modem.
Todate there is no general switching device which will permit a computer to interconnect with two devices connected to the switching device to permit different interconnected modes of operation of the devices in a universally adaptable way without the use of dedicated circuitry in the devices themselves.
It is an object of the invention to attempt to provide a software controlled switch device that will permit devices to be controlled by a computer for particular interconnected modes of operation without the need for dedicated hardware in the devices themselves. In a particular implementation, the switching device is controlled by control signals that issue from a serial output COM port of a PC. In this way, devices intended for connection with the PC via an output port can be controlled for interconnected modes of operation.
In accordance with the first broad aspect of the present invention there maybe provided a method of using a computer and a switching device to switch two devices connected to said switching device into different interconnected modes of operation, said method involving:
a) providing software in the computer permitting interface to request different interconnected modes of operation of said two devices,
b) causing a first switching signal to be generated by said software in response to a request for one particular interconnected mode of operation,
c) receiving that first switching signal at said switching device and controlling two switch means in said switching device with said first switching signal to provide one of four possible interconnected modes of operation of said two devices, each of said two switch means having respective ON and OFF states,
whereby providing a second switching signal will provide a second possible interconnected mode of operation, providing a third switching signal will provide a third possible interconnected mode of operation, and providing a fourth switching signal will provide a fourth possible interconnected mode of operation.
Preferably there is the further step of passing said first switching signal to an output port of the computer and from said output port to said switching device.
Preferably the first second, third and fourth switching signals are provided by. ON and OFF signals respectively on two lines of said output port.
Preferably said two lines are two lines of a serial output COM port of said computer.
According to a further broad aspect of the present invention there is provided a switching device for use with a computer, and computer software therefor, said switching device permitting two devices connected thereto to be switched into different interconnected modes of operation,
said switching device having two switch means, each having respective ON and OFF states,
said switching device being responsive to a first switching signal generated by said computer and said software in response to a request for one particular interconnected mode of operation, so said switch means will interconnect said two devices into the one interconnected mode of operation,
and where a second switching signal will interconnect said two devices into a second interconnected mode of operation, a third switching signal will interconnect said two devices into a third interconnected mode of operation, and a fourth switching signal will interconnect said two devices into a fourth interconnected mode of operation.
Preferably, said switching device is responsive to ON and OFF signals appearing on two lines of an output port of said computer, said ON and OFF signals, providing the respective first, second, third and fourth switching signals depending on the combinations of ON and OFFs appearing on said two lines as set by said software.
Preferably said two lines are on a serial output COM port of said computer.